Torque wrench



June 17, 1952 W, H, MAYR 2,601,044

TORQUE WRENCH Filed Jan. 6, 1949 Patented June 17, 1952 UNITED STATES PATENT OFFICE A 1 Claim.

This invention relates to a torque wrench. The invention is particularly useful in connection with a wrench which is adjusted for exerting limited torque in the rotating of a nut or other object, the structure permitting ratcheting of the wrench shaft during the operation.

An object of the invention is to provide a torque wrench of few parts which is effective for exerting limited torque in the turning of an object while at the same time permitting ratcheti'ng of the shaft during the turning operation. A further object is to provide a unitary torque wrench shaft equipped with `means cooperative with a spring plunger for exerting a desired amount of torque upon an object to be rotated, while at the same time permitting easy ratcheting of the shaft in the operation of the Wrench shaft. A further object is to provide a novel plunger structure cooperating with a cam wrench and a shaft for effecting turning of an object while at thesame time permitting the ratcheting of the shaft in such operation'. Other specific objects and advantages will appear as the specification proceeds.

The invention is shown in an illustrative embodiment by the accompanying drawing, in which- Fig. 1 is a perspective view of a wrench structure embodying my invention; Fig. 2, a transverse sectional view; Fig. 3, a sectional view, the section being taken as indicated at line 3-3 of Fig. 2; and Fig. 4, a perspective view of the wrench shaft and associated plunger spring and cap parts employed in the wrench embodying my invention.

In the illustration given, Il) designates a casing which may be formed of metal or other suitable material. In the illustration given, the casing I provides a tubular casing portion II providing a passage receiving the wrench shaft I2, and a tubular portion I3 providing a passage intersecting the wrench shaft passage, as shown more clearly in Figs. 2 and 3. The casing I0 is shown in the form of a T but it may be in the shape of an L or any other desired shape.

The wrench shaft I2 is equipped at its outer end with a reduced squared end I4 and the end may be provided with a spring-urged ball I5, as shown more clearly in Fig. 2. The end I4 is adapted to be inserted in a square socket of the nut or other part to be rotated. It will be understood that the end I4 may be of any desired shape for use in engagement with a socket or other part to be engaged for rotating an object.

To retain the shaft I2 Within the casing extension Il, a pin I6 may be passed through the casing portion II so as to engage an annular groove I'I formed within the shaft I2.

The inner end of the shaft I2 is provided with cam surfaces I8, as shown more clearly in Figs. 3 and 4. Each of the .cams I8 is provided with a ridge portion I9 which is rather steeply .inclined and with a slightly inclined and partially downwardly inclined ratchet portion 20.. Between ridge portions I9 and ratchet portions 20 there are provided depressed portionsZB of reduced radius as seen more clearly in Fig. 3. It will be noted that ridge portions I9 provide surfaces of rapidly increasing radius, while ratchet portions 20 provide surfaces of gradually increasing radius.

Cooperating with the cam surfaces is a plunger 2I having an elongated rounded end 2'2 bearing against the cam surface I8. The elongated or ridged end 22 cooperates with the sharply inclined portion I9 of the cam I8 for rotating the shaft I2, While the slightly inclined portion 20 of the cam permits the plunger end 22 to ratchet over said portion 20 as the casing I0 is rotated in a counter-clockwise` direction as-shown in Fig. 3.

A spring 23 normally urges the plunger 2| toward the cam portions I 8 of shaft I2. The spring is tensioned by means of a screw cap 24 having a slot 25 therein for receiving the end of a screwdriver, and on its inner side the cap 24 may be provided with a pin 26 received within the spring 23.

In the operation of the structure, the shaft I2 is placed Within the tubular casing portion II and secured therein by driving the pin I6 through the casing portion into engagement with the annular groove I'I. The shaft I2 may thus rotate with respect to casing portion II while being held against longitudinal movement.

The spring-urged plunger 2| engages the cam surfaces I8 and when the casing I0 is rotated in one direction so that the ridge portion I9 of the cam bears against the plunger end 22 while it is seated within the depressed portion 28, the shaft I2 is held against turning and the desired amount of turning force is applied tov the nut or other object to be rotated. On the other hand, when the casing IIJ is rotated in the opposite direction the handle casing I0 carries the plunger end 22 out of the depressed portion 28 over the cam surface 20 to permit it to engage the ridge portion I9 of the next cam surface I8. Thus, as one looks at the structure shown in Fig. 3, the casing IIJ may be rotated in a clockwise direction to effect turning of the shaft I2 and the nut engaged thereby, and then the casing I2 may be swung in a counter-clockwise direction with the plunger end 22 sliding over the cam portion 20 until the next ridge portion I9 is engaged, at which time the shaft I2 may be again rotated to the left to effect another partial turning of the nut or other object to be rotated.

After the nut has been tightened to the desired point, the ridge portion I9l of the cam I2 is no longer effective in locking the shaft I2 to the casing I0, and the plunger 2| yields or ratchets over the cam portion I9. The wrench thus becomes inoperative for further turning movement of the nut, Should it be desired to increase or diminish the torque of shaft I2, a screwdriver or other blade may be applied to the slot 25 of cap 24 and the cap may be adjusted longitudinally of the casing portion I3 to increase or diminish the compression of spring 23. The threaded cap 24 engages a relatively long threaded portion 21 in the casing portion I3 so that substantial adjustment can be effected by rotating the member 24. I

The casing I in the T-shape illustrated is useful in that the T portion of the casing provides a handle by which the tubular portion II may be rotated in both directions during theL movement of shaft I2 in one direction while ratcheting backwardly over the cam surface 20 of shaft I2 in the other direction.

In the structure shown, a single shaft I2 which is integral is employed not only as the torque shaft but as a ratcheting means, the main operating parts being the single shaft and the spring-urged plunger cooperating therewith. It will be understood that any number of cam surfaces I8 may be provided. I have shown four cams but the number may be varied as desired.

While in the foregoing specication, I have shown a single structure in considerable detail for the purpose of illustrating an embodiment? of the invention, it will be understood that such details of structure may be varied widely by those skilled in the art without departing from the spirit of my invention.

I claim:

In a torque Wrench of the type having a T- shaped casing providing a shaft-receiving portion having a shaft passage therein and a handle portion having a plunger passage therein intersecting said shaft passage, a shaft rotatably received in said shaft passage and having an outer end shaped for locking engagement with an object to be rotated and having also an inner end provided with a plurality of cam surfaces, each of said cam surfaces having a depressed portion of reduced radius between a steeply curved ridge portion of rapidly increasing radius and a slightly curved ratchet portion of gradually increasing radius, a plunger slideably mounted in said plunger passage and having an inner rounded end engagedly with said shape cam surfaces and adapted to seat in the said depressed portions thereof, and spring means for yieldably urging said plunger against said cam surfaces with selectively variable pressure, whereby on rotation of said handle in one direction the rounded end of said plunger is locked within one of said depressed portions against the adjacent ridge portion until a torque is developed suicient to overcome the selected spring pressure on said plunger, while upon rotation of said handle in the opposite direction said rounded end slides out of said depressed portion onto said ratchet portion and rides over said cam surfaces.

WILLIAM H. MAYER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,328,087 LeChot Jan. 13, 1920 2,332,972 Johnson Oct. 26, 1943 2,503,499 Livermont Apr. 11, 1950 2,536,225 Rice Jan. 2, 1951 2,556,587 Keen June 12, 1951 

